Why am I so possessive?

What Guys Said 1

You have insecurities and you are somewhat of a control freak, that would be my guess. You can't just sit back and trust, you have to manage every bit of risk by snuffing it out before it even happens. Possessiveness is very close to obsessiveness.

You can't stop someone from cheating if they choose to do so, therefore it is futile to waste your energy. In doing so you just increase the likelihood of killing the relationship yourself.